Changes in work schedule affect headache frequency among Norwegian nurses: a 3-year-follow-up study.

OBJECTIVES: To explore whether changes in work schedule, number of night shifts and number of quick returns were related to changes in headache frequencies. METHODS: A longitudinal study with questionnaire data from 2014 (baseline) and 2017 (follow-up) on work schedule (day only, shift work without nights and shift work with nights), number of night shifts, number of quick returns (less than 11 hours in-between shifts) and validated headache diagnoses among 1104 Norwegian nurses. Associations were explored by adjusted multivariate regression analyses. RESULTS: The median age at baseline was 37 years (IQR 31-43) and 90.5% were women. In the adjusted logistic regression analysis of changed work schedule between baseline and follow-up, changing from night work was associated with increased odds for reversion from headache >1 days/month to no headache at all last year (OR 2.77 (1.29; 5.95)). Changes towards less night shifts (>10) or quick returns (>10) during the last year were associated with increased odds of reversion of headache to no headache (OR 2.23 (1.20; 4.17) and OR 1.90 (1.04; 3.49)). Only decrease in number of night shifts (>10) during the last year reduced risk of onset of any new headache between baseline and follow-up (OR of 0.39 (0.18; 0.84)). CONCLUSION: Changing from night work and reducing the number of night shifts and quick returns were associated with less headache in this 3-year-follow-up of Norwegian nurses. This adds to the growing body of evidence that night work may have direct negative health consequences.

A shift to something better? A longitudinal study of work schedule and prescribed sleep medication use in nurses.

OBJECTIVES: To explore whether a change in work schedule was associated with a change in the probability of prescribed sleep medication use. METHODS: A longitudinal study with annual questionnaire data (2008/2009-2021, except 2019) on work schedule (day work only, shift work without nights and shift work with nights) and prescribed sleep medication use from 2028 Norwegian nurses (mean age 31.7 years, 90.5% women at baseline) who participated in the ongoing Survey of Shift work, Sleep and Health (SUSSH). Associations were estimated using a random effects model, and a fixed effects regression model in which nurses were included as their own control to account for potential unobserved confounding. RESULTS: In both models, day work was associated with a more than 50% lower probability of sleep medication use compared with shift work with nights (adjusted OR (aOR) 0.50, 95% CI 0.27 to 0.93 in the random effects model, and an aOR 0.32, 95% CI 0.14 to 0.70 in the fixed effects regression model). Shift work without nights was associated with a non-statistically significant reduction in sleep medication use within nurses in the fixed effects regression model when compared with shift work with nights (aOR 0.66, 95% CI 0.37 to 1.20). CONCLUSIONS: Day work was associated with a significant reduced probability of prescribed sleep medication use compared with shift work with nights. This indicates that quitting night work will improve sleep and thereby reduce hypnotic use.

Fish consumption, sleep, daily functioning, and heart rate variability.

STUDY OBJECTIVES: This study investigated the effects of fatty fish on sleep, daily functioning and biomarkers such as heart rate variability (HRV), vitamin D status (serum 25-hydroxyvitamin D (25OHD), and eicosapentaenoic acid (EPA, 20:5n-3) + docosahexaenoic acid (DHA, 22:6n-3) in red blood cells. Moreover the relationship among sleep, daily functioning, HRV, vitamin D status, and levels of EPA+DHA was investigated. METHODS: Ninety-five male forensic patients from a secure forensic inpatient facility in the USA were randomly assigned into a Fish or a Control group. The Fish group received Atlantic salmon three times per week from September to February, and the Control group was provided an alternative meal (e.g., chicken, pork, beef), but with the same nutritional value as their habitual diet, three times per week during the same period. Sleep (sleep latency, sleep efficiency, actual sleep time, and actual wake time), self-perceived sleep quality and daily functioning, as well as vitamin D status, EPA+DHA, and HRV, were assessed pre- and post-intervention period. RESULTS: There was a significant increase in sleep latency from pre- to post-test in the Control group. The Fish group reported better daily functioning than the Control group during post-test. Fish consumption throughout the wintertime had also an effect on resting HRV and EPA+DHA, but not on vitamin D status. However, at post-test, the vitamin D status in the Fish group was still closer to the level regarded as optimal compared to the Control group. Vitamin D status correlated negatively with actual wake time and positively with sleep efficiency during pre-test, as well as positively with daily functioning and sleep quality during post-test. Finally, HRV correlated negatively with sleep latency and positively with daily functioning. CONCLUSIONS: Fish consumption seemed to have a positive impact on sleep in general and also on daily functioning, which may be related to vitamin D status and HRV.